(a) Field of the Invention
An apparatus and method for monitoring multiple micro-cores are provided, and more particularly, a technology for allowing one watchdog to monitor a plurality of micro-cores.
(b) Description of the Related Art
Generally, an electronic control unit (ECU) mounted to vehicles includes a micro-core monitoring circuit configured to monitor an operation state of the micro-core. However, a vehicle-stability improvement device (for example, an anti-lock brake system (ABS), a traction control system (TCS), an electronic stability control, a vehicle dynamic control (VDC) system, etc.) directly affects safety of a vehicle and occupants during braking and driving of the vehicle. Therefore, if the electronic control unit (ECU) malfunctions, it may result in the occurrence of an accident.
When a micro-core monitoring circuit for use in the ECU detects an abnormal program execution process by monitoring a program execution process of the micro-core, the micro-core monitoring circuit prevents the ECU from malfunctioning, resulting in improved safety of a vehicle and thus its occupants.
Preferably the micro-core is operated in a flexible manner. However, there is a very low possibility that an unexpected problem occurs in the micro-core because of an unknown reason, such that a watchdog periodically monitors the micro-core and recognizes the presence or absence of an error in the micro-core.
FIG. 1 (PRIOR ART) is a conceptual diagram illustrating a conventional micro-core monitoring apparatus.
Referring to FIG. 1, if a micro-core 10 operates normally, the micro-core 10 outputs a pulse-wave clear signal to a watchdog 20. In this case, the micro-core 10 periodically outputs the clear signal within a predetermined time. If the watchdog 20 periodically receives the clear signal from the micro-core 10, the watchdog 20 determines that the micro-core 10 operates normally.
Upon receiving no clear signal from the micro-core 10 within the predetermined time, the watchdog 20 determines the presence of a problem in the micro-core 10. Accordingly, the watchdog 20 outputs a pulse-wave reset signal to the micro-core 10 so as to reset the micro-core 10.
In general, multiple micro-cores are being embedded in most semiconductors. For example, a dual-core or at least four micro-cores may be embedded into the semiconductor. As a result, as many watchdogs as the number of micro-cores can be embedded in the semiconductor so as to monitor individual micro-cores.
The number of watchdogs is identical to the number of multiple micro-cores, and several watchdogs are separately coupled to the multiple micro-cores. The watchdogs can independently check the presence or absence of an error in the multiple micro-cores. However, if the watchdogs are respectively coupled to the micro-cores, the size of a semiconductor device unavoidably increases.